FRIDAY, Jan. 12, 2018 (HealthDay News) -- The worst flu season in years is only getting worse, with 49 states now seeing widespread misery, U.S. health officials report.

"Flu is everywhere in the U.S. right now," Dr. Daniel Jernigan, director of the U.S. Centers for Disease Control and Prevention's influenza division, said during a media briefing Friday. On a map of the United States tracking flu activity, "this is the first year that we have had the entire continental U.S. be the same color," he noted.

Only Hawaii and the District of Columbia have been spared widespread flu infection so far, according to the CDC.

"There has been a very rapid increase in the numbers of people coming in to see their doctors. The season has started early, and it is probably peaking right about now," Jernigan added.

Not only that, but "there is also a rapid rise in the number of people being hospitalized for laboratory-confirmed flu," Jernigan said. In just the past week, hospitalizations have almost doubled, going from 13.7 per 100,000 to 22.7 per 100,000.

The highest rates of hospitalizations are among those over the age of 65, but hospitalizations for those 50 to 64 is also high and increasing, Jernigan noted. And 20 children have died from the flu so far this season.

An imperfect vaccine and a long bout of cold, wintry weather have conspired to turn this flu season into a very severe one, health officials have said.

It's no secret by now that the flu vaccine is not a good match with the H3N2 flu strain that is dominating the season.

At this point, 80 percent of reported flu cases are this more severe strain, according to the CDC. And Jernigan said he expected this year's vaccine to be about 30 percent effective against H3N2 when all is said and done.

Unfortunately, the end of this flu season is nowhere in sight.

"There are at least 11 to 13 more weeks of influenza to go," Jernigan said. "In addition, there are still other strains of influenza yet to show up. We know that B viruses will be showing up later in the season. We are also seeing H1N1 starting to show up in states that have already had H3 activity."

Still, H3N2 is the far nastier strain, and tends to be very bad news for the very young and the very old.

The vaccine may be less effective against H3N2 strains because it's manufactured in chicken eggs, which some recent research has shown interact with H3 strains, making them less like the circulating strain and therefore less effective.

Even though the vaccine may not be well matched, it doesn't mean you shouldn't get a flu shot, CDC officials say. It's still the best protection against H3N2 flu and other flu strains, such as H1N1 and B viruses.

According to CDC director Dr. Brenda Fitzgerald, "While our flu vaccines are far from perfect, they are the best way to prevent getting sick from the flu, and it is not too late to get one."

So far, more than 151 million doses of vaccine have shipped, Fitzgerald said at the media briefing.